One example of a conventional underwater mobile inspection apparatus is a remotely operated underwater vehicle (see Patent Literature 1, for example). The remotely operated underwater vehicle is configured to inspect and clean a subsea structure such as a tubular member installed on the seafloor while running on the subsea structure via casters. An operator can control the remotely operated underwater vehicle by operating a ground-based control device while viewing the subsea structure from the ground via a video camera provided on the remotely operated underwater vehicle.
The remotely operated underwater vehicle allows the operator to operate a large number of thrusters, manipulators, and the like provided on the vehicle from the ground, and therefore, the operator can control the vehicle to move under water in a flexible manner like the operator him or herself, thereby inspecting and cleaning the subsea structure.